Robotic wash cell using recycled pure water

ABSTRACT

The present invention pertains to a robotic wash cell including a six-axis robotic arm and end effector equipped with nozzles that spray unheated, solvent free, pure water at high-pressure to clean or debur objects by maintaining the nozzles in close proximity and substantially normal to each surface being cleaned or edge being deburred. The robotic cell wash is particularly useful for cleaning contaminants such as oil and grease from items having more complex shapes. The six-axis robotic arm positions the nozzles and their sprays substantially normal to each surface being cleaned or deburred. The nozzles produce a multi-zone spray pattern with a continuous effective cleaning zone. A water recycling and pressurizing system collects the used water, separates out the oil and grease contaminants to a level of about 5 ppm, and pressurizes the pure water to about 3,000 psi for washing operations or about 6,000 psi for deburring operations.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of and claims the priority of U.S.patent application Ser. No. 11/405,656 filed on Apr. 17, 2006, entitled“Method Of Washing A Contaminant From A Surface Via A Robotic Arm” thecontents of which are relied upon and incorporated herein by referencein their entirety which application is a division of application Ser.No. 10/926,855, filed on Aug. 26, 2004, now U.S. Pat. No. 7,054,717,which is a division of application Ser. No. 10/271,517, filed on Oct.16, 2002, now U.S. Pat. No. 6,804,579, and the benefit of priority under35 U.S.C. 119(e) is hereby claimed.

FIELD OF THE INVENTION

The present invention relates to a robotic wash cell using a recycled,pure water system that includes a six-axis robotic arm and end effectorequipped with nozzles that spray unheated, solvent free, high-pressurewater to clean oil films from or debur an object by maintaining thenozzles in close proximity and substantially normal to each surfacebeing cleaned or edge being deburred.

DESCRIPTION OF THE PRIOR ART

Various factors affect the design of a robotic wash system. Thesefactors include the size, shape and texture of the object or item beingcleaned, the material or contaminant being removed, and whether theworking fluid is recycled, contains a cleaning solvent or is heated.Robotic wash systems for small and mid size objects, such as cars, carbody carriers and painting masks frequently use a wash cell or booththat encloses the item and wash system. Larger objects such asairplanes, ship cargo holds and storage tanks, frequently require aportable robot that is brought to or placed inside the object beingcleaned. Some systems are designed to remove paint from the surface ofthe item while others are designed to remove a contaminant such as oilor grease. Some criteria allow the spray to slightly erode the itemwhile others do not. Examples of various robotic washing and cleaningdevices are discussed and shown in U.S. Pat. No. 4,817,653 to Krajicek,U.S. Pat. No. 5,038,809 to Rodgers, U.S. Pat. No. 5,358,568 to Okano,U.S. Pat. No. 5,248,341 to Berry and U.S. Pat. No. 5,454,533 to Grant,the disclosures of which are incorporated by reference herein.

Robotic wash systems include a variety of components. They typicallyinclude a robotic device and corresponding control system, a workingfluid for washing the object, a pump to pressurize the fluid, nozzles tospray the fluid at the object, and an end effector or frame to supportthe nozzles. Detergents or other chemical solvents are usually added tothe wash spray to improve cleaning effectiveness. The wash system caninclude a closed room or cell that contains the robotic arm, objectbeing cleaned and working fluid spray. Wash cells help prevent workrelated injuries and accidents that can arise due to inadvertent contactwith the rapidly moving robotic arm or its heated, pressurized spray.Wash cells also help contain the spray and its chemical that enter theair in the form of a mist or increased humidity. This helps maintain themanufacturing plant and its air supply in a desirable condition. Someexamples of wash cells are described in U.S. Pat. No. 4,220,170 toHebert, U.S. Pat. No. 4,629,409 to Satoh and U.S. Pat. No. 4,850,382 toWilliams, the disclosures of which are incorporated by reference herein.

Wash systems are often designed to recycle the working fluid after it issprayed. The sprayed fluid is typically collected and passed through oneor more filters or separators to remove the contaminants and debris.Examples of some conventional recycling wash systems are described inU.S. Pat. No. 4,029,114 to Wiltrout, U.S. Pat. No. 4,652,368 to Ennis,U.S. Pat. No. 5,059,332 to Satoh, U.S. Pat. No. 5,501,741 to McMahon,U.S. Pat. No. 5,593,598 to McGinness, U.S. Pat. No. 5,665,245 to Kloss,U.S. Pat. No. 6,402,855 to Damron and U.S. Pat. No. RE 37,674 to Carter,the disclosures of which are incorporated herein.

Conventional robotic wash systems have difficulties cleaningcontaminants such as oil and grease from an object, particularly whenthe working fluid is being recycled. Oil and grease can leave a thinfilm on the surface of the object even after it is washed. This filmcauses manufacturing problems when the object is being handled in otherareas of the plant. Conventional wash systems add solvents and heat tohelp break down the oil or grease. These solvents and the increased mistand humidity due to the heat can damage the components and joints of therobotic arm. Yet, waterproofing the robotic arm is expensive anddifficult to maintain. Heated working fluids also increase the rate atwhich biological contaminants grow in the fluid system and inside thewash cell. These biological contaminants pose a health hazard to thepeople working in the plant, and can damage the robotic arm and othercomponents in the wash system.

Solvents also make it difficult to recycle the working fluid. Solventstend to mix or otherwise combine with the water and oil or grease tocreate emulsions. These emulsions are difficult to filter out orseparate from the water without using expensive and bulky filtrationsystem. The oil emulsions adhere to the pipe walls and clog the nozzlesand other components in the system. The emulsion build up on the pipesand components creates a resilient layer that has a dampening effect onthe pressurized system. The dampening effect causes delays to pressurechanges in the working fluid, such as when the system is turned on oroff. The oil emulsions also attacks the pump seals and other componentsin the system. Economical and efficient high-pressure water pumps haveseals that require the working fluid to have 5 parts per million (ppm)of oil or less to avoid frequent maintenance shut downs. The entire washsystem may need to be shut down and flushed every few hundred hours toclean, refurbish or replace the piping, components and pump seals. Thismaintenance is expensive and can render the system unacceptable for manyindustrial applications where such delays adversely affect the overallefficiency of the entire manufacturing process.

Another problem with conventional wash systems is that they requirelarge quantities of water and take up large amounts of floor space. Thefilters and separator in the recycling system require a significantamount of time to separate the contaminants and emulsions from the waterin order to achieve the desired purity levels of the system. As aresult, a large quantity of inactive water must remain in these filtersand separators in order to support a relatively small volumetric flowthrough the spray nozzles. These filters and separators are alsorelatively large so that even a small wash cell requires a significantamount of plant floor space.

An additional problem with conventional robotic wash systems is thatthey lack the range of motion needed to use pure water to completelyremove contaminants like oil from an object, particularly objects havingmore complex shapes. Conventional five-axis robotic arms and devices arenot suitable for a pure water wash cell system. These robotic arms havedifficulty positioning and articulating the spray nozzles to spraydirectly at or normal to the surface of the object being cleaned. Thewater sprays strike many surfaces of the object at angles that cannotcompletely remove an oil film layer. It has been found that angles ofgreater than about 7.degree. degrees from normal start to deterioratethe cleaning effectiveness of a pure water spray for the purpose ofremoving oil and grease from the surfaces of an object. While aconventional five-axis robotic arm might be able to wash a flat trayplaced in direct alignment with the robotic arm, these arms do notprovide a sufficient range of motion to enable them to handle mostobjects. These robotic arms lack the flexibility to get into the nooksand crannies found in the vast array of items that need to be cleaned inmany manufacturing settings. Items with surfaces that face in differentdirections or are offset from the main axis of the robotic arm, or itemshaving a number of projections or recesses in those surfaces areparticularly troublesome. Five-axis arms also have difficulty or areincapable of cleaning surfaces with small areas that must be avoided toprevent damage to sensitive components.

A further problem with conventional robotic wash systems is that theyhave a limited spray width. In order to clean an item with a largesurface area, the robotic arm must move back and forth across a surfacemany times. This increases the time the robot needs to get the itemthrough the wash cell and reduces the overall capacity of the system.While some wash systems attempt to increase the spray width by aligninga number nozzle on a bulky frame to repeatedly clean a specific objectwith a specific shape, these systems are not designed to handle a widevariety of item shapes and sizes found in a manufacturing setting. Inaddition, the bulky frame may require hundreds of nozzles to clean alarge item such as an airplane.

A still father problem with an array of aligned spray nozzles is thatthe nozzles have to be a certain distance from the surface of the itemto perform properly. Adjacent nozzles with diverging sprays tend tointersect each other so that the overall spray pattern completely coversan area in a single pass. These diverging sprays pose problems forrobotic applications that manipulate the spray nozzles through severalpasses over an object, particularly objects with more complex shapes.The width of the diverging spray varies when the nozzle is closer to orfurther away from the surface being washed. When the nozzles are tooclose to a surface, there are gaps between adjacent sprays so that thesurface is not completely cleaned. When the nozzles are too far from thesurface, adjacent sprays intersect, which tends to reduce the cleaningeffectiveness of the sprays. This is particularly true for ahigh-pressure spray system where intersecting portions of spays havesignificantly reduced pressure and effective cleaning power.

A still further problem with conventional wash systems is that theirusefulness is limited to cleaning the item. The systems cannot beadapted to provide an additional function such as deburring the surfacesor edges of the item. Capital expenditures for another robotic cell andfluid system are needed to provide the deburring operation.

A still further problem with conventional wash systems is that the endeffector is not able to remove various types of debris from the item sothat the wash nozzles can clean the entire item. In a manufacturingsetting, debris and garbage such as dirty rags, towels, cans, paper bagscan be left on an item moving along a conveyor system leading to thewash cell. The high-pressure water jets do not produce enough volumetricflow to blow this debris off the item during the wash cycle. As aresult, portions of the item may be missed. The item may need to betaken off the conveyor system downstream of the wash cell and returnedfor additional cleaning.

The present invention is intended to solve these and other problems.

SUMMARY OF THE INVENTION

The present invention pertains to a robotic wash cell including asix-axis robotic arm and end effector equipped with nozzles that sprayunheated, solvent free, pure water at high-pressure to clean or deburobjects by maintaining the nozzles in close proximity and substantiallynormal to each surface being cleaned or edge being deburred. The roboticcell wash is particularly useful for cleaning contaminants such as oiland grease from items having more complex shapes. The six-axis roboticarm positions the nozzles and their sprays substantially normal to eachsurface being cleaned or deburred. The nozzles produce a multi-zonespray pattern with a continuous effective cleaning zone. A waterrecycling and pressurizing system collects the used water, separates outthe oil and grease contaminants to a level of about 5 ppm, andpressurizes the pure water to about 3,000 psi for washing operations orabout 6,000 psi for deburring operations.

The present robotic wash cell and water system invention cleanscontaminants such as oil and grease from an object having a solidsurface without using solvents, detergents or other cleaning agents. Thehigh-pressure, pure water spray efficiently and thoroughly cleans oil orgrease from the surfaces of the item being washed. No significant traceor film of oil or grease remains on the surfaces of the item after it iswashed. This is a significant advantage for many manufacturing processeswhere the presence of an oil or grease film can result in manufacturingproblems that would otherwise require the item to be manually cleaned.

The present robotic wash cell and water system invention uses unheated,solvent free pure water as its working fluid. The pure water sprayproduced by the system does not create significant amounts of water andoil emulsions, such as those associated with wash systems usingdetergents or other solvents. The ambient temperature of the water sprayfurther reduces the amount of emulsions and significantly reduces theamount of mist and humidity inside the cell. The water spray doesevaporate or float in the air as readily as in heated systems. The washcell has an air filtration system that is able to easily handle the mistand humidity that do occur. As a result, the robotic arm operates in amore friendly environment that is less contaminated with corrosivechemicals, and costly maintenance and waterproofing of the robotic armare avoided or minimized. The ambient temperature spray alsosignificantly reduces the growth of biological contaminants in the washcell and water system that would otherwise pose a health risk to thepeople in the plant or damage the robotic arm and other components inthe system.

The present robotic wash cell invention can thoroughly cleans objects byarticulating its six-axis robotic arm to aim its high-pressure, purewater spray substantially normal to each surface being cleaned andmaintain the nozzle in close proximity to these surfaces as the roboticarm and water spray move across them. The water is preferablypressurized to about 3,000 psi and maintained within a continuousefficient cleaning zone about eight to ten inches from the surface ofthe object during each cleaning pass. The sixth axis of the robotic armallows it to articulate the water spray as it moves along a cleaningpath along a particular surface so that the spray remains normal orsubstantially normal to that surface, as well as at the edge orintersection of two adjacent surfaces. This articulating,high-pressurized water spray maintains its cleaning effectivenessthroughout the cleaning of the object. The robotic wash system is ableto substantially completely clean oil or grease films from many surfacematerials, including metal, plastic, ceramic or painted surfaces in acost effective and time efficient manner. The wash system has been foundto be particularly effective at cleaning oil and grease films from thealuminum surfaces of many automotive components.

The present pure water wash system conserves water. Chemical emulsionsthat commonly occur in heated, solvent or detergent based wash systemsare avoided so that the water supply can be economically recycled. Thefiltration system includes a small tank, and relatively inexpensivefilters, plate separator for removing the oil contaminants andultraviolet germicidal treatment unit to inhibit the growth of germs andbacteria Expensive and bulky filtration, separation and treatmentsystems are not necessary.

The present robotic wash cell and recycled pure water system achieves ahigh level of water purity and requires minimal maintenance. The systemcan remain operating for 6,000 hours between scheduled maintenanceintervals. This significantly long operating duration increases thecapacity and overall efficiency of the system and the entire plant,particularly plants having assembly lines and just-in-timemanufacturing. The present robotic wash system also achieves waterpressures of 1,000 to 6,000 psi by using conventional high-pressurepumps with low maintenance ring seals. By eliminating solvents and theemulsions they produce, the system is able to achieve a water puritylevel having suspended solids of 30 microns or less, oil concentrationsof 5 ppm or less, and a water temperature of 120.degree. F. or less.This water purity and low temperature allows the system to use aconventional ring seal pump capable of achieving 6,000 psi. This pumpalso avoids heating the water. Expensive pumps with packed seals andshort maintenance intervals are not necessary. In addition, oilemulsions that would otherwise adhere to the pipe walls or otherwiseclog the nozzles and other components in the system are minimized tohelp achieve the long operating duration of the system. As a result, thepresent invention is ideally suited for many industrial applications.

Another advantage of the present wash system invention is that itrequires a relatively small quantity of water and fits into a relativelysmall area of floor space. The oil separator fits inside a relativelysmall 100 to 250 gallon tank. A large portion of the water supplyremains actively flowing through the pipes, pumps and spray nozzles. Thesize of the filters and separator are also small enough to justify arelatively small wash cell to accommodate a plant with a limited amountof available floor space.

A further advantage of the present robotic wash cell invention is itsability to wash a wide variety of objects, including those with morecomplex shapes. The robotic wash cell includes a six-axis robotic armthat accommodates a wide variety of objects. Although the robotic arm issecured to the floor, ceiling or other supporting surface in the washcell, the robotic arm is flexible enough to allow a range of motion andarticulation of the nozzles and water spray to reach the varioussurfaces of a wide variety of objects. The robotic arm directs the endeffector, nozzles and spray normal to each of the various surfaces whilemaintaining the nozzles in close proximity to each surface beingcleaned. The robotic arm is able to follow the contour of the objectincluding its projections and recesses. The robotic arm can also move incloser to clean some areas more vigorously than others, or avoiddesignated areas that should not be cleaned to avoid damaging a sensoror other sensitive part. Accordingly, the robotic wash cell is suitablefor a wide variety of commercial applications and manufacturingsettings.

A still further advantage of the present robotic was h, system is itsrelatively wide spray width. While keeping the weight of the endeffector to a minimum, the present invention uses a limited number oftwo or more nozzles aligned to produce a spray pattern with a continuousworking region of sufficient width to quickly clean an item with a largesurface are. The robotic arm is programmed to move over the contours ofthe object in a multi-direction, multi-pass manner. By aligning two ormore nozzles, the robotic wash cell is able to effectively clean largeror more complexly shaped objects in relatively few wash paths. Thisincreases the through speed or capacity of the robotic wash cell so thatit can clean a large number of objects in a relatively short period oftime.

A still further advantage of the robotic wash cell is that itsindividual high-pressure sprays are offset so that they do notintersect. Each nozzle produces a diverging spray so that adjacentsprays begin to overlap at a set distance of about eight inches from thenozzle. Yet, each nozzle is offset or rotated a slight amount about itscentral axis so that adjacent sprays are parallel but do not intersect.As a result the entire spray pattern strikes the surface being cleanedwith a substantially uniform pressure or cleaning power. The amount ofpressure or cleaning power depends on the distance the nozzle is fromthe surface being cleaned, not whether the surface is in an area ofintersecting sprays with reduced cleaning power. When the nozzles arepositioned about eight to ten inches from the surface being cleaned,adjacent sprays do not leave a gap between them. Instead, they create acontinuous, substantially uniform zone with an effective cleaning powerthat the robotic arm is free to manipulate to efficiently clean itemswith complex shapes.

A still further advantage of the present wash system is its ability todebur the surface of the item. The wash nozzles on the end effector canreadily be replaced with debur nozzles. The high-pressure pump is theneasily switched to pressurize the water to about 6,000 psi or more byreducing the volumetric rate of water supplied to the pump and nozzles.Capital expenditures for an additional deburring station are avoided.

A still further advantage of the present wash system is its ability toclear or remove various types of debris from the item so that it canclean or debur the entire item. The end effector includes nozzles forblowing a large volume of air that combines with the high-pressure waterspray to blow or sweep away any debris on the item. Debris and garbagesuch as dirty rags, towels, cans, paper bags that are inadvertently lefton an item in a manufacturing setting are swept away by the combinedsprays. As a result, the system is capable of reliably cleaning theentire item without missing areas that may be covered by debris andgarbage.

Other aspects and advantages of the invention will become apparent uponmaking reference to the specification, claims and drawings.

DESCRIPTION OF THE DRAWING

FIG. 1 is a schematic view of the present robotic wash cell andrecycling and pressurization system showing the flow path of the workingfluid through its pumps, screens and filters, and oil separator andultraviolet treatment unit.

FIG. 2 is a perspective view of the present robotic wash cell inventionshowing a robotic arm with six axes of rotation mounted on a track onthe ceiling of the wash cell, with the arm shown in phantom sweeping oneof two transmission pans placed on a frame that is supported by aconveyor.

FIG. 3 is a top plan view showing the conveyor system aligning the frameand transmission pans relative to a set of predetermined coordinates atthe corner of an alignment mechanism.

FIG. 4 is a perspective view of the present invention cleaning atransmission housing having a body with generally conical shape, anumber of axial and longitudinally extending ribs or flanges projectingfrom the surface of the body, and a sensor.

FIG. 5 is a top view of the end effector with two water nozzles and fourair nozzles, and showing the water nozzles slightly offset so that theirdiverging spray patterns do not intersect.

FIG. 6 is a rear sectional view of the end effector of FIG. 5 showingthe water spray patterns beginning to overlap at a distance of eightinches from the tip of the nozzles.

FIG. 7 is a front view of a debur end effector equipped with anauto-rotate debur nozzle with two offset water jets, each jet spraying22.degree. off the nozzle centerline.

FIG. 8 is an elevation view of the robotic arm mounted on a pedestalanchored to the floor with the robotic arm on one side of a complex itemresting on a table with the robotic arm positioning its end effector anddebur nozzle in close proximity to the item with its sixth axis rotatedto direct the debur nozzle normal to the surface of the item.

FIG. 9 is an elevation view of the robotic arm of FIG. 8 and reachingover the complex item and table with its sixth axis rotated to directthe debur nozzle back at the item.

FIG. 10 is a top plan view showing the robotic arm moving the endeffector and nozzles a long a path of travel over multiple horizontalsurfaces of the transmission pan while maintaining the nozzle spraynormal to the surfaces being cleaned.

FIG. 11 is a side view of FIG. 10 showing the nozzle spray alignednormal and in close proximity to the surface being cleaned.

FIG. 12 is a side sectional view showing the robotic arm and endeffector aligned to direct its spray substantially normal to thevertical side wall of a recess in the transmission pan.

FIG. 13 is a side view showing the robotic arm moving along a linearpath to clean the top surface of an item and articulating along itsfifth axis to move along another linear path of travel to clean one ofthe side surfaces of the item.

FIG. 14 is a side view of the robotic arm moving along a linear path oftravel into the page to clean the top surface of the item, and showingthe end effector in phantom articulating along its sixth axis to cleanthe front side of the item.

DETAILED DESCRIPTION

While this invention is susceptible of embodiments in many differentforms, the drawings show and the specification describes in detail apreferred embodiment of the invention. It should be understood that thedrawings and specification are to be considered an exemplification ofthe principles of the invention. They are not intended to limit thebroad aspects of the invention to the embodiment illustrated.

The present invention relates to a robotic wash cell using a recyclingpure water system that is generally indicated by reference number 50 andshown in FIGS. 1 and 2. The robotic wash cell 50 is particularly suitedto clean objects 4 that are at least partially covered or coated with acontaminant such as oil or grease. Oil and grease are particularlydifficult to clean or remove from an object 4 because they form a thinfilm that clings to the surfaces of the object. The present invention isable to clean these contaminants and their films from objects 4, evenwhen the object has a more complex shape.

Objects 4 with complex shapes have several surfaces that face indifferent directions, and include objects 4 with areas that need to becleaned more thoroughly or sensitive areas that should not be cleaned atall. An example of a complex shaped object 4 is a transmission pan 5shown in FIGS. 2 and 3. The pan 5 includes a number of surfaces 7 a-efacing different directions, an outer rim 8, a recess 10 with sidewallsurfaces 11 that are normal or otherwise angularly oriented to the uppersurface 7 a, and a projection 15 with sidewall surfaces 16 that arenormal or angularly oriented to each other and the upper surface 7 a.The outer end of the projection 15 has an area 17 that needs to becleaned particularly thoroughly. The pan 5 has a sensitive area 18containing a sensor 19 that should not be exposed to a high-pressurewater spray. An example of another complex shaped object 4 is atransmission housing 25 shown in FIG. 4. The housing 25 has acone-shaped body 26 with lower and upper ends 28 and 29 with a matrix ofoutwardly extending axial 32 and longitudinal 34 rims. The wider lowerend 28 is placed on the floor so that the axial rims 32 are extendedhorizontally around the body 26 and the longitudinal rims 34 extendsubstantially vertically toward the upper end 29. The upper end 29 issomewhat square and has a number of projections 40.

The robotic wash cell 50 generally includes a floor 51, walls 52 and aceiling 53 that define an enclosed chamber 54 as shown in FIG. 1. Thecell 50 has access openings (not shown) through which objects 4 andworkers can enter and leave the chamber 54. A transport apparatus 60moves and orients the object 5 relative to specific recognizedcoordinates 55 in the chamber 54 as shown in FIGS. 2 and 3. Thetransport apparatus 60 moves the items into the chamber 54 one at a timeor in groups of two or more. When two transmission pans 5 are moved asshown, they are placed on a rack or frame 65 having a front end 66 andlateral sides 67. Each pan 5 is fixed to or otherwise securely placed onthe frame 65 at a specific location and orientation relative to theframe. The pans 5 are oriented so that their front and side edges areparallel to the front 66 and sides 67 of the frame 65, respectively, andare each a predetermined distance from a corner 68 of the frame.

The transport and alignment apparatus 60 can take a variety of formssuch as a conveyor 71 and alignment mechanism 81. The conveyor 71 hasside rails that support spaced rollers 72 upon which the item 5 ispropelled via gravity or drive rollers. The conveyor 71 is substantiallyhorizontal a location where a stop 75 is located and where the item 5will be cleaned. The alignment mechanism 81 includes an L-shaped bracket82 having a forward segment 84 with a forward edge 85 and lateralsegments 86 with a lateral edge 87. The forward and lateral edges 85 and87 meet to form a corner 88. The forward edge 85 of the bracket 82flushly engages the forward edge 66 of the frame, and stops the forwardmovement of the frame 65 and items 5 at a desired position. Apositioning mechanism 89 then pushes the item against the lateral edge85, and aligns the item 5 in a desired orientation relative to a set ofpredetermined coordinates 55, such as the corner of the alignmentbracket. The height of the conveyor 30 positions the item 5 a desireddistance from the floor 51 of the wash cell. The alignment mechanism 81includes an L-shaped alignment member 82 with forward and lateralsegments 84 and 85 adapted to engage the front and side of the frame 65upon which a number of items 5 are placed. The forward movement of theframe 65 causes it to engage and align flushly against the front 84 ofthe alignment member 81. A lateral press 89 engages the frame 65 andmoves it flush against the lateral segment 86. In this way, the conveyor71 and alignment mechanism 81 align the frame 65 and the items 5 itcarries to a set location relative to predetermined coordinates 55 or 88inside the wash cell 20.

Although the transport and alignment apparatus 60 is shown and describedas a conveyor 71 with an alignment mechanism 81, it should be understoodthat this apparatus can take many forms without departing from the broadaspects of the invention. For example, the transport apparatus can be agantry that moves the item into and out of the wash cell 50 and alignsand places the item 5 at a desired location relative to specificcoordinates 55. It can also be a track and cart rig that stops the itemat a desired location relative to specific coordinates 55, or a roboticarm programmed to align and locate the item at a desired locationrelative to specific coordinates. A manual system of moving and aligningthe item can also be used. These various transport apparatus shouldpreferably locate and align the item to within about ⅛ to ¼ inch of thedesired location relative to the predetermined coordinates 55.

The robotic wash cell 50 includes an end effector 100 as in FIGS. 5 and6. The end effector 100 is preferably symmetrical and has a solid base102 with a predetermined length that defines a centerline or centerlineof mass 103. The base 102 rigidly supports two parallel, spaced apartmounting brackets 104 and 105 that are generally normal to thecenterline 103. The end effector is aimed in a direction 106 generallynormal to its centerline 103. The first or inner mounting bracket 104rigidly supports a set of conventional air nozzles 110. The second orouter mounting bracket 105 rigidly supports a set of conventionalhigh-pressure water nozzles 130. The mounting brackets 104 and 105 aregenerally spaced apart to accommodate the two sets of nozzles 110 and130.

The set of air nozzles 110 preferably includes four nozzles 111 that areevenly spaced across the mounting bracket 104 at about two inchincrements on center. Two nozzles 111 are symmetrically located on eachside of the centerline 103 of the end effector 100. Each air nozzle 111has a generally flat body 112. Each nozzle 111 has an inlet 114 forreceiving pressurized air, and a head 115 with an outlet 16 that spansits width of about 1½ inches. Air is supplied to the nozzle inlet 114 ata pressure of about 60 psi via a conventional air hose 119. Air exitseach outlet 116 at a rate of about 60 cubic feet per minute (cfm) and aspeed of about 85 miles per hour (mph). The nozzles 111 are parallel toeach other and parallel to the direction of aim 106 of the end effector100. The nozzles 111 combine to produce a spray pattern 120. The airnozzles 111 are preferably Model No. AA727 nozzles made by SprayingSystems Company of Wheaton, Ill.

The set of water nozzles 130 preferably includes two conventionalhigh-pressure water nozzles 131. Each water nozzle 131 has a generallytubular body 132 that defines a centerline 133. The nozzles 131 arerigidly attached to the mounting bracket 105 and spaced about two inchesapart on center. The centerline 133 of each nozzle 131 is normal to andsymmetrically located about one inch from the centerline 103 of the endeffector 100. The water nozzles 131 are spaced about 2¾ inches from theair nozzles 111. The nozzle 131 has an inlet 134 that receiveshigh-pressure water, and a head 135 with a narrow outlet 136 that formsan orifice or point of impingement for spraying the high-pressure water.The orifice 136 is located on the centerline 133 of the nozzle.Pressurized water is supplied to the nozzle inlet 134 via a conventionalhigh-pressure hose 139 in the range of about 1,000 to 5,000 psi. Whencleaning oil from an aluminum surface, the inlet pressure is preferablyabout 3,000 psi, and the water exit rate per outlet is about 3.5 gallonsper minute (gpm) per nozzle with a subsonic spray speed of about 400mph. The nozzles 131 have an impingement efficiency of about 65 percentThe centerlines 133 of the nozzles 131 are parallel to each other, andparallel to the direction of aim 106 of the end effector 100. The waternozzles 131 are preferably a PowerJet Model No. 38955-04 nozzles made bySpraying Systems Company.

Pressurized water is sprayed from each nozzle 131 in the form of adispersing spray 141 as shown in FIGS. 5 and 6. The orifice or point ofimpingement 136 of each nozzle 131 preferably has a generallyrectangular shape to produce a generally thin, fan shaped spray 141emanating from the orifice. Each spray 141 has a centerline 143 that isa linear extension of the centerline 133 of its nozzle 131. Each spray141 is symmetrical about its centerline 143 and has generally linearside edges as shown in FIG. 5, and a generally planar layer in thedirection of aim 106 as shown in FIG. 6. Each side of the spray 141angles from the centerline 133 at an angle of about 7½.degree. Theimpingement power or cleaning effectiveness of the spray 141 remainssubstantially constant between a range of about two inches to abouteight inches from the orifice 136. At a distance of about ten inches,the spray 141 retains about 80 percent of this impingement power. Aftera distance of about ten inches, the integrity and shape of the spray 141begins to disintegrate, and its impingement power and cleaningeffectiveness start dropping off exponentially.

Each spray 141 has an effective washing range for cleaning films such asoil of about one inch to about ten inches when the water is supplied at3,000 psi. A stand off distance of about one to two inches from thenozzle head 135 produces vigorous washing that actually heats thesurface and its oil film. This is an area 145 of ultra high-pressure orcleaning power. A stand off of about four to six inches produces hardwashing that can penetrate or blast through a pool of water in a recess.This is an area 146 of very high-pressure or cleaning power. A stand offof about eight to ten inches produces effective washing thatsubstantially completely removes an oil film from a metal surface at areasonable rate of speed for the intended purpose of this particularrobotic wash system, such as an end effector 100 speed of about twoinches to about one foot per second. This is an area of effectivewashing power 147. Each spray 141 retains an effective washing pressureor cleaning power above a working limit of about 2,000 psi through thiswashing range 147 when a contaminant such as oil is being cleaned from amaterial such as metal. This working limit can be dropped to about 600psi for cleaning oil form materials such as plastic. In this embodiment,a stand off of about eight to ten inches is effective for cleaning anoil film from an aluminum surface using a robotic arm speed of about twoinches to about one foot per second. Each spray 141 retains a thicknessof about 1/16 to ⅛ inch at a distance or stand off of eight inches fromthe orifice 136. Additives are not added to the water to maintain theintegrity and effectiveness of the spray 141 for longer distances,because presently known additives are hazardous and difficult to use ina recycling water system. The flow of water to one of the nozzles 131can be turned off when the end effector 100 comes in close to a surfaceas in region 151 so that the spray only impacts a specific area.

The individual sprays 141 combine to produce a multi-zone spray pattern150 shown in FIG. 5. The spray pattern 150 is divided into threedistinct zones or regions 151, 152, and 153 as it progresses outwardlyfrom the nozzles 131. The first region 151 includes discrete sprays 141and a gap 156 between these adjacent sprays. This region 151 extendsfrom the nozzle head 135 of the adjacent nozzles 131 to a distance ofjust less than about eight inches from the orifices 136 taken alongcenterline 133 to the location 157 where the sprays begin to overlap.The discrete sprays 141 widen and the gap 156 narrows as the sprays moveaway from the nozzle heads 135. The concentration of the sprays 141 andtheir pressure or cleaning power is greatest in this first region 151.As discussed above, when the nozzle head 135 is within about one to twoinches of the surface being cleaned, the sprays 141 impact the surfacewith such force that they actually heat the surface and the oil orgrease contaminant as it is being removed. In this ultra high-pressureregion 145, the sprays 141 must be rapidly moved along the surface toavoid unnecessary erosion of the surface being cleaned.

The second region 152 of the spray pattern 150 begins at the location orboundary 157 where the adjacent sprays 141 begin to overlap. Each spray141 has a width of about two inches and the spray pattern 150 has acontinuous width of about four inches. The area of overlap 158 widens asthe spray pattern 150 extends beyond eight inches. The spray pattern 150formed by the individual sprays 141 of the set of nozzles 130 combine toform this continuous effective working region 152 with a depth thatextends from about eight inches to about ten inches from the nozzleheads 135 and their outlets 136. Although there is no clearly definedboundary demarcating where the second region 152 ends, this regiongenerally extends to a location or boundary 159 where the pressure orcleaning power of the sprays 141 and spray pattern 150 falls below adesired level practical for the particular robotic application beingperformed. In this embodiment, the desired level is about 2,000 psi andthe outer boundary 159 of the individual sprays 141 and the effectiveworking region 152 is about ten inches.

The third region 153 of the spray pattern 150 extends beyond the outerboundary 159 of the continuous effective wash area 152. The individualsprays 141 begin to deteriorate in this region 153. Adjacent sprays 141begin to intersect in the overlapping areas 158 to form a more turbulentspray of pressurized water. The force or power of the disintegratingwater spray 150 remains effective for general sweeping of dirt anddebris from the surfaces of the item 5 but is not generally sufficientto substantially completely remove contaminants such as oil and greasefilms in a time efficient manner using a robotic system. Although thereis no clear outer boundary demarcating where the third region 153 ends,this region generally extends to about one to five feet from the nozzles141. The pressurized air spray from the air nozzles 111 will tend to mixwith the water spray 150 in this outer region 153.

As best shown in FIG. 6, each nozzle 131 and its spray 141 is rotated aslight amount about its centerline 133 so that the individual sprays 141do not intersect each other in the area of overlap 154, at least insideregions 151 and 152. When the nozzles are two inches apart, an angle ofabout 2.degree. is typically sufficient to keep the sprays fromintersecting in regions 151 and 152. Intersecting sprays 141 tend todrop the effective washing pressure below the desired working limit ofabout 2,000 psi, as discussed above. This drop in pressure isundesirable because it can prevent the formation of the continuouseffective cleaning zone 152 with a sufficient depth usefuel for roboticapplications.

Although the end effector 100 is shown and described with a set 130 oftwo water nozzles 131 that produce two individual sprays 141, it shouldbe understood that the end effector could have one water nozzle to keepthe weight of the end effector to a minimum or three or more waternozzles to produce a wider spray pattern 150 without departing from thebroad aspects of the invention. The geometry of the multi-zone spraypattern 150 could also be modified without departing from the broadaspects of the invention. For example, the nozzles 131 can be movedcloser together to draw in the inner location 157 defining the beginningof the effective working region 152, or by increasing the pressure ofthe water supplied to the nozzles 131 so that the outer boundary 158moves further away from the nozzles.

The robotic wash cell 50 also uses a debur end effector 170 fordeburring items 5 as shown in FIG. 7. The end effector 170 is preferablysymmetrical and has a solid base 172 with a predetermined length thatdefines a centerline or centerline of mass 173. The base 172 rigidlysupports a mounting bracket 174. The mounting bracket 174 rigidlysupports a conventional debur water jet nozzle 181. The end effector 170is aimed in a direction 176 generally normal to its centerline 173.

The debur nozzle 181 has a generally tubular body 182 that defines acenterline 183. The centerline 183 of the nozzle 181 is normal to andintersects the centerline 173 of the end effector 170. The nozzle 181has an inlet 184 for receiving high-pressure water, and a head 185 withtwo outlets or orifices 186 that spray two relatively solid streams orjets 190 of high-pressure water. The pressurized water is supplied tothe nozzle inlet 184 via a conventional high pressure hose 189 in therange of about 5,000 to 15,000 psi, and preferably at about 6,000 psifor deburring an aluminum object 4. Each jet 190 has a diameter of about50 thousandth of an inch. The head 185 is rotatably attached to the body182. Each orifice 186 is offset from the centerline 183 of the nozzleabout one inch, and canted or angled about 22.degree. from thecenterline 183 of the nozzle 181. The orifices and water jets 190 areangled to point in opposed directions. The offset and angle of the waterjets 190 cause the head 185 to automatically rotate about its centerline183 at a high rate of speed so that the jets 190 form a conical spraypattern 195 with a centerline 197. The debur nozzle 181 is preferablyAquajet Model No. RD1000 nozzle of Hammelmann, Inc. located in Dayton,Ohio.

The deburring effectiveness of the jets 190 remains substantiallyconstant to a distance of about two to six inches from the orifice 186.At a distance of about six inches, the jets 190 retain about 80 percentof their effectiveness. After a distance of about one foot, theintegrity and shape of the jets 190 begins to disintegrate, and theirdeburring effectiveness starts dropping off exponentially. Each jet 190has an effective deburring range of about ⅛ inch to about six inches foreffective deburring of a metal item at a linear speed of about one halfinch to about three inches per second. The jets 190 retain an effectivedeburring pressure above a desired working limit of 4,500 psi throughits effective deburring range for deburring soft aluminum. This limitincreases to about 12,000 psi for deburring hard steel. Each jet 190retains a thickness of about 50 thousandths of an inch at a stand off ordistance of about six inches to one foot from the orifice 186. Again,additives are not added to the water to maintain the integrity andeffectiveness of the spray 190 for longer distances.

The robotic wash cell 50 includes a conventional six-axis robotic arm200. The end effector 100 or 170 is rigidly mounted to the robotic arm200, which moves and articulates the end effector to wash or debur theobject 4. The robotic arm 200 can be anchored to the ceiling 53 as inFIG. 2, the floor as in FIGS. 8 and 9, or any other supporting surfacein the wash cell 50. The ceiling mount allows the robotic arm 200 to belocated above the item 4 when it is brought into the wash cell 50, andcan be raised above the working area of the wash cell 50 so that it isout of the way and does not interfere with or become damaged by the item4 as it is moved into and out of the wash cell 50.

The robotic arm 200 has a base 211, inner arm segment 221, outer armsegment 231, wrist 251 and mount 261. These components are robustlydesigned to carry the weight of the arm 200 and its end effector 100 or170 so that there is relatively minimal deflection in the arm 200 whenit is fully extended or moved at a high rate of speed. The componentsare firmly connected to each other so that there is relatively minimalplay as the arm 200 moves from one position to another or the directionof the spray 150 or 190 is altered. The robotic arm is preferably aModel IRB2400-16F robotic arm made by ABB, Inc. of Auburn Hills, Mich.

The base 211 has a mount 212 and a rotatable portion or turret 213. Themount 212 is rigidly secured to the floor 51, ceiling 53 or othersupporting surface. The turret 213 is rotatably secured to the mount 212via a rotatable joint 215 having a central axis 216 that constitutes themain axis of the robotic arm 200. The central axis 216 is generallyaligned normal to the horizontal ceiling 53, but could be mounted at anangle to the floor 51, ceiling 53 or conveyor 71 if desired. The mainaxis 216 of the robotic arm 200 remains fixed inside the cell 50relative to the floor 51 or ceiling 53 as in FIGS. 2, 8 and 9. Duringuse, the turret 213 is free to rotate about this axis 216 so that thearm 200 can be directed to extend in any rotational direction relativeto this axis of the arm.

The first or inner arm segment 221 has a predetermined length with innerand outer ends. The inner end is pivotally joined to the turret at afirst pivot joint 225 that allows the upper arm 221 to pivotally rotateabout a first pivot axis 226 relative to the base 211. The inner armsegment 221 and its pivot joint 225 allow the arm 200 to be raised orlowered vertically from the ceiling 53. The axis 226 of the inner armsegment 221 is generally perpendicular to the axis 216 of the base 211,and remains horizontal to the floor 51 or ceiling 53. During the use ofa ceiling mounted robotic arm 200, the inner arm segment 221 istypically pivoted to a lower position to provide generally horizontalmovement of the end effector 100 or 170 along the item being cleaned 5.

The second arm segment or forearm 231 has a predetermined length and aninner portion 232 with inner and outer ends. The inner end is pivotallyjoined to the outer end of the upper arm 221 at a second pivot joint 235that allows the forearm 231 to pivotally rotate about a second pivotaxis 236 relative to the inner arm segment 221. This axis 236 of theforearm 231 is generally parallel to the axis 225 of the upper armsegment 221 and perpendicular to the axis 216 of the base 211. Duringuse, the forearm 231 and joint 235 allow the end effector 100 or 170 togenerally move vertically toward the item 5 as in FIG. 2, or along oneof its vertical sides. The forearm 231 also has an outer portion 242with inner and outer ends. The inner end is rotatably joined to theouter end of the inner portion 232 at a second rotation joint 245 havinga central axis 246. The second portion 242 is free to rotate about thecentral axis 246. The central axis 246 is normal to the pivot axis 236of the forearm 231. During use, the second portion 242 and joint 245allow the arm 200 to rotate end effector 100 into a direction of aim 106toward the item 4 being cleaned when the arm is moving along the sidethe item.

The wrist 251 is pivotally joined to the outer end of the outer portion242 of the forearm 231 at a third pivot joint 255 to allow the wrist torotate about pivot axis 256. The pivot axis 256 is generally parallel topivot axis 226 and 236 and normal to the central axis 246 of the forearm231. During use, the wrist 251 and joint 255 allow the arm 200 to rotateor articulate the end effector 100 or 170 and spray 150 or 190 from adirection substantially normal to the top surface of the item 4 to adirection substantially normal to the side surface of the item as shownin FIG. 13. However, this articulation of the end effector 100 will onlymaintain proper normal alignment of the nozzles 131 and spray 150 to thesurface of the item 5 when the item is aligned directly under the mainvertical axis 216 of the robotic arm 200. When the surface being cleanedis offset from this axis 216, joint 255 will not, by itself or inconjunction with the joints 215, 225, 235 and 245, be able to maintainits direction of aim 106 of nozzles 131 and spray 150 substantiallynormal to that surface while moving the end effector 100 along thissurface, particularly while holding the head 135 of the nozzles 131 afixed distance from that surface.

The mount 261 is rotatably joined to the wrist 251 at a third rotationjoint 265 having a central axis 266 as shown in FIGS. 6-9, 13 and 14.The mount 261 is free to rotate about the central axis 266. The mount261 has a proximal end 268 for securely mounting the end effector 100 or170. The central axis 266 is generally linearly aligned with the centralaxis 246 of the forearm 231 when positioned as in FIGS. 2, 6 and 7, butis angularly offset from axis 246 when the wrist 251 is rotated aboutaxis 256 as in FIGS. 8, 9, 13 and 14. During use, the mount 261 andjoint 265 allow the arm 200 to transition from a first path of travelalong one surface of the item 4 to a new path of travel along anadjacent surface. The new path of travel can be either parallel orperpendicular to the first path of travel. The mount 261, end effector100 or 170, and nozzles 131 or 181, are rotated about axis 266 so thatthe spray 150 is angled or normal to the new path of travel as shown inFIG. 13. The combination of the six joints 215, 225, 235, 245, 255 and265 allows the direction of aim 106 of nozzles 131 and 181, sprays 141,150 and 195 to remain substantially normal to each surface of the item 4being cleaned while moving the end effector 100 along various paths oftravel over its various surfaces and while simultaneously holding thehead 136 of the nozzles a fixed distance from each surface, even whenthose surfaces are offset from the main axis 216 of the robot 200. Thedirection of aim 106 and centerlines 143 or 197 of the sprays 141 or 195preferably remain within 5.degree. of normal to the surface beingcleaned.

Each of the six joints 215, 225, 235, 245, 255 and 265 in the roboticarm 200 includes a separate servo motor (not shown) for selectivelyrotating or pivoting its associated member 211, 221, 231, 242, 251 and261. Each servo motor, and thus the movements of the joints, members androbotic arm 200, is programmably controlled by a conventional controlsystem 270, such as the Model No. S4C control system of ABB, Inc. Thecontrol system includes a controller 272, an input terminal 274 and amonitor 275. An operator programs the robotic arm 200 and end effector100 to move along particular linear and arcuate paths of travel and toarticulate the end effector 100 or 170 and nozzles 131 or 181 through awide range of motions to clean the desired surfaces of the object 5.

Water Recycling and Pressurization System

A recycling and pressurization system 300 is shown in FIG. 1. The pumpmotors and other operating components in this system 300 are preferablyprogrammably controlled by the computer control system 270 withallowable manual overrides to adjust or fine tune the system. After thewater sprays 150 or 190 clean the surface of the item 5, thecontaminated water falls via gravity to the floor 51 of the wash cell50. The unfiltered water and oil fluid mixture flows via a conventionalfloor drain system (not shown) to collect in a sump 305. Water and oilemulsions are kept to a minimum because the sprays 150 do not usedetergents or other solvents to help remove the oil and grease from theobject being cleaned, and because the water spray 150 remains betweenambient temperature and 120.degree. F. The fluid in the sump 305 is atambient temperature.

The water and oil mist suspended in the air inside the wash cell 50 isdrawn through a demist unit 310 having a conventional scrubber impingerunit via a conventional blower with a 5 horsepower (HP) motor capable ofmoving 4,500 cubic feet per minute (cfm). The air drawn into the demistunit 310 in replaced by unfiltered, ambient air via a duct or air intake(not shown). The contaminated fluid collected by the scrubber impingerunit 310 is routed to the sump 305. The demisted air passes through anultraviolet (UV) treatment unit to kill any bacteria or microorganismsand a silencer to minimize acoustic noise.

The unfiltered water and oil fluid mixture flows from the sump 305 at arate of 3 to 10 gallons per minute (gpm) via one foot of gravitypressure through a screen (not shown) that removes solids from thefluid. The fluid then flows to a conventional pneumatic pump 320 capableof producing 10 psi at 11.5 gpm. The pump 320 pressurizes the fluid toabout 5 psi and moves it at a rate of 3 to 10 gpm. The fluid is atambient temperature as it flows to a 100 to 250 gallon stainless steeltank containing a conventional oileophelic plate-type separation unit330 for separating unfiltered water and oil fluid mixture. The separator330 produces water containing no more than 5 (ppm) of oil. The separatorunits is preferably a Plate-Pak separator made by Freytech, Inc. ofFlorida Separated oil flows via a gravity drain 332 at a rate of 0 to6.5 gpm where it is recoverable to a composition of 99.99% oil, 0.002%water and 0.008% solids. Makeup water is added to the system via theseparator 330 at a rate of about 100 gallons per day (gpd). This makeupwater is taken from standard city tap water having a temperature ofambient to 45.degree. F. and filtered 333 via a conventional reverseosmosis filter 333 to a filtration level of 15 ppm of total dissolvedsolids. The separator 330 is provided with a gravity drain 337 capableof draining 0 to 3.5 gpm of overflow water from the separator. Aconventional UV treatment unit 335 that kills any biological ormicroorganisms in the water is also placed in the stainless steel tank.The UV treatment unit 335 is preferably a Model No. TM13 treatment unitmade by Atlantic Ultraviolet, Inc. of New York.

Pure, unfiltered, ambient temperature water flows from the separator 330at a rate of about 7 gpm via three feet of water pressure to aconventional centrifugal pump 340 with a 1.0 HP motor. This booster pump340 pressurizes the water to 55 psi and moves the fluid at a rate ofabout 7 gpm to a conventional 30 micron element filter 350 capable offiltering 20 gpm of water at a pressure of 100 psi. Ambient temperaturewater leaves the filter 350 at pressure of about 50 psi at a rate ofabout 7 gpm, and a purity level of 5 ppm of oil and total dissolvedsolids no larger than 20 to 30 microns.

The fluid then passes through a conventional piston plunger pump 360driven by a conventional 15 HP motor that pressurizes the water to about3,050 psi and moves the working fluid at a rate of about 7 gpm. The pumpis preferably a Model No. HDP22 pump made by Hammelmann, Inc., which iscapable of pressurizing the pure water to up to about 15,000 psi. Thewater leaving the pump 360 is between ambient temperature and120.degree. F. The pump has a sensor activated switch (not shown) thatautomatically shuts off the pump should the water temperature exceed120.degree. F. This pure, filtered water is delivered to the washnozzles 131 at about ambient temperature and 3,000 psi. A water pressureof about 6,000 psi for the debur nozzles 181 is attained by reducing therate of fluid flow through the piston pump 360 to about half or 3.5 gpm.

The system 300 has been disclosed to use a water supply of pure water.Pure water does not contain detergents, solvents, chemicals or additivesto enhance the cleaning ability of the water, other than the typicalagents found in a public water system or softened well system. Purewater is economical, easily accessible to manufacturing plants, andhelps avoid or minimize the formation of oil emulsions. However, itshould be understood that although the working fluid of the system 300is preferably pure water, it should be understood that other workingfluids that do not tend to form oil emulsions when sprayed athigh-pressure to clean a contaminant such as oil or grease could also beused as the working fluid of this system.

Operation of Robotic Wash Cell

Although the following should be understood given the above discussion,the following is provided to assist the reader in understanding theoperation of the robotic wash cell 50 in the preferred embodiment Thetransport apparatus 60 such as a conveyor 71 moves an item 4 such astransmission pan S into the wash cell 50. The transporter 60 ispreferably programmably controlled by the control system 270. The item 5contains an oil film on its surfaces. The item 5 moves along theconveyor 71 until it reaches a desired work area at a known height inthe room 50 and triggers a mechanism such as a sensor or switch to stopthe forward motion of the item. The alignment mechanism 81 thenpositions the item 5 so that it will remain fixed at a particulardesired position relative to a set of predetermined coordinates 55 knownto or programmed into the controller 272. The item 5 is then ready to becleaned.

The object 5 is first swept by the robotic arm 200 and end effector 100to remove any loose dirt or debris. The robotic arm 200 is equipped withan end effector 100 for washing the item 5. The arm 200 is brought downfrom its home position near the ceiling 53 of the wash cell 50. Theconventional air system (not shown) and water system 300 are activatedto supply air at about 60 psi and water at about 3,000 psi to the inlets114 and 134 of nozzles 111 and 131, respectively. The robotic arm 200then programmably moves the end effector 100 to a start position aboutone to four feet above the main upper surface of the item 5 based on thepredetermined coordinates 55 of the item, and articulates the endeffector so that its direction of aim 106 is substantially normal tothis surface. The robotic arm 200 then moves in a series of programmedpaths of travel above the main upper surface of the item 5 whilemaintaining its direction of aim 106 substantially normal to this mainupper surface to dislodge and blow away the loose dirt and debris. Thepaths of travel are linear or arcuate to correspond to the shape orcontour of the main upper surface of the item and maintain the one tofour foot clearance between the nozzle heads 115 and 135 and thatsurface. When necessary, the robotic arm will also move the end effectorto a position along side the item about one to four feet from the mainside surface of the item, and articulates the end effector 100 so thatits direction of aim 106 is substantially normal to that main sidesurface. The arm will then move in one or more programmed paths oftravel along the main side surface while maintaining the direction ofaim 106 and distance of the nozzles 131 substantially normal to and oneto four feet from this main side surface and to further dislodge andblow away the loose dirt and debris. If necessary, this sweepingoperation can be repeated for each main surface of the item.

The object 5 is now ready to,be cleaned by the robotic arm 200 and endeffector 100 to substantially completely remove the oil and grease fromits surfaces. The air system for nozzles 111 is turned off. The watersystem 300 continues to supply water at about 3,000 psi to the inlets134 of water spray nozzles 131. The robotic arm 200 then programmablymoves the end effector 100 to a start position with the nozzle heads 131positioned about eight inches from an end of a first particular surface7 a-e based on the predetermined coordinates 55, and articulates the endeffector 100 so that its direction of aim 106 is substantially normal tothis surface. The robotic arm 200 then programmably moves the endeffector 100 along a path of travel along this surface while maintainingits direction of aim 106 substantially normal to this surface andmaintaining its eight inch stand off distance. The effective workingregion 152 of the spray pattern 150 remains in contact with thissurface. The path of travel is programmed to closely follow the contourof the surface. The path of travel can be linear as when cleaning a side7 b-e of the transmission pan 5 shown in FIG. 10, or can be arcuate aswhen cleaning around the conical outer surface 30 of the transmissionhousing 25 shown in FIG. 4. When the width of the spray pattern 150 iswider than the surface being cleaned, such as surface 7 b-e, only onepass along that surface is needed. When the width of the spray pattern150 is narrower than the surface being cleaned, such as surface 30, thenthe robotic arm 200 programmably moves along one or more similar pathsof travel, each being spaced about one spray width from and parallel tothe previous path of travel. The robotic arm 200 continues to maintainits direction of aim 106 substantially normal to this surface andmaintain its eight inch stand off distance. This process is performedfor each particular surface that is to be cleaned.

When the robotic arm 200 and end effector 100 comes to a recess 10 or 38or a projection 15 or 40 in the particular surface 7 a or 30 beingcleaned, the robotic arm 200 programmably articulates the end effector100 and spray 150 to a direction of aim 106 normal to one of the wallsformed by that recess or projection as shown in FIG. 12. The robotic arm200 programmably articulates the end effector 100 and spray 150 to cleaneach sidewall surface of the recess or projection.

The robotic arm 200 and end effector 100 are able to avoid a sensitivearea 18, such as an area containing a sensor 19. When the robotic arm200 is moving along a path of travel and reaches a predeterminedlocation in front of the sensitive area, the robotic arm 200programmably articulates the end effector 100 to rotate the direction ofaim 106 of the spray pattern 150 out of its normal alignment and awayfrom contact with sensitive area so that the spray pattern 150 does notcontact the sensitive area This articulation is done while the arm 200continuously moves along its path of travel. After the robotic arm 200moves to a predetermined location past the sensitive area, the armprogrammably articulates the direction of aim 106 of the end effector100 back normal to the surface being cleaned.

The robotic arm 200 can also be programmed to move the end effector 100close to a particularly difficult to clean surface or area of the item.The robotic arm 200 articulates the direction of aim 106 of the endeffector 100 normal to this surface or area, and positions the endeffector 100 close enough to the surface that the ultra high-pressure145 or very high-pressure 146 regions of a particular spray 141 impactthe desired difficult to clean area. The robotic arm 200 then movesalong a path of travel to clean the difficult area. If the difficultarea is particularly small, the robotic arm may simply articulate thespray 141 to clean the area. If the difficult area is particularly largeso that the width of the spray 141 is narrower than the difficult area,then the robotic arm 200 programmably moves along one or more similarpaths of travel, each being spaced about one spray 141 width of theselected region 145 or 146 from and parallel to the previous path oftravel. The robotic arm 200 continues to maintain its direction of aim106 substantially normal to this surface and maintain its desirablyclose stand off distance.

The surfaces of an object with offset parallel surfaces, such as thetransmission housing 25 in FIG. 4, can be cleaned relatively quickly bythe end effector 100 and robotic arm 200. This is because the effectivecleaning area 152 of the spray pattern 150 has a depth of about twoinches. The outer surface 30 of the housing is extensively covered byand array of axial and longitudinal rims 32 and 35. The outer ends ofthe ribs 32 and 35 are parallel to and offset about one-half inch fromthe outer surface 30. The robotic arm 200 can be programmed to positionthe end effector 100 so that the nozzle heads 135 are about eight inchesfrom the ends of the ribs 32 and 35 and about 8½ inches from the outersurface 30, and articulate the end effector so that its direction of aim106 is normal to both of the parallel offset the surfaces. The roboticarm 200 can then programmably move the end effector 100 along an arcuatepath of travel around the circumference of the housing 25, or along alinear path of travel along the height of the housing, whilesimultaneously maintaining its aim 106 normal to both of these paralleloffset surface to simultaneously clean both surfaces in a single pass.The sidewall surfaces 33, 34, 36 and 37 of the housing are cleaned viaseparate passes similar to that shown in FIG. 4.

The robotic wash cell 50 is able to clean the various surfaces of theobject 4 by programming the six axis robotic arm 200 to move andarticulate the end effector 100 through multiple paths of travel whilemaintaining the end effector in close proximity to the these varioussurfaces and maintaining the aim 106 of the end effector and spray 141and 150 normal to these surfaces. In this way the wash cell 50 is ableto substantially completely clean or remove any oil or greasecontaminant from the various surfaces of objects having even complexshapes. Although microscopic amounts of oil or grease particles mayremain, the surfaces of the object 4 are completely clean or free of anyoil or grease when subjected to a close visual examination, and thepresence of oil or grease is undetectable to the touch.

The robotic wash cell 50 can also be used to debur the edges of theobject 4. The wash end effector 100 is removed and the debur endeffector 170 is rigidly mounted to the robotic arm 200. The air systemremains off and water system 300 is adjusted to supply water at about6,000 psi to the inlet 184 of nozzle 181. The robotic arm 200 thenprogrammably moves the end effector 170 to a start position about two tosix inches from an edge formed by two adjacent surfaces of the item 5based on the predetermined coordinates 55 of the item, and articulatesthe end effector 170 so that its direction of aim 106 is substantiallynormal to one of these surfaces. The robotic arm 200 then programmablymoves the end effector 100 along a path of travel along this surfacewhile maintaining its direction of aim 106 substantially normal to thissurface and maintaining its two to six inch stand off distance. Theeffective working region of the spray 195 remains in contact with thissurface and its edges. The path of travel is programmed to closelyfollow the contour of the surface. The path of travel can be linear aswhen deburring the edges of the surfaces 7 of the transmission pan 5shown in FIG. 2, or can be arcuate as when deburring the edges of theconical surfaces of the ribs 32 and 35 of the transmission housing 25shown in FIG. 4. When the edges are relatively far apart as with pan 5,only one edge can be deburred in a single pass. When several edges arerelatively close together, and the width of the spray 195 is narrowerthan the entire span of edges as with housing 25, then the robotic arm200 programmably moves along one or more similar paths of travel, eachbeing spaced about one spray width from and parallel to the previouspath of travel. The robotic arm 200 continues to maintain its directionof aim 106 substantially normal to the various surfaces and maintain itstwo to six inch stand off distance from their corresponding edges. Thisprocess is performed for each particular edge that is to be deburred.

While the invention has been described with reference to a preferredembodiment it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted withoutdeparting from the broad aspects of the invention.

1. A robotic wash cell for washing a contaminant from a surface of anobject, said wash cell having a supporting surface and a source ofhigh-pressure fluid, the object being placed relative to specificpredetermined coordinates inside said robotic wash cell, said roboticwash cell comprising: a robot having at least six axes of rotation andan arm having a proximal end and a main axis, the surface of the objectbeing offset from said main axis; an end effector having a nozzle, saidend effector being secured toward said proximal end of said robotic arm,said end effector and nozzle having a direction of aim, the source ofhigh-pressure fluid being flowably connected to said nozzle tocontrollably deliver the high-pressure fluid to said nozzle, said nozzlefor a dispersing spray in said direction of aim; and, a control unithaving a controller and an input device to selectively control said sixaxes of rotation to move said end effector and nozzle along a path oftravel a desired distance from the surface of the object, said desireddistance, and said robotic arm articulating said end effector and nozzleand their said direction of aim to remain substantially normal to thesurface of the object as said robotic arm moves said end effector alongsaid path of travel, said spray substantially completely removing thecontaminant from the surface of the object.
 2. The robotic wash cell of1 wherein said dispersing spray has a predetermined effective workingrange.
 3. The robotic wash cell of 1 wherein said fluid is water.
 4. Therobotic wash cell of 1 wherein said dispersing spray has an increasingwidth dimension which is substantially normal to said path of travel andsaid spray has an effective working range.
 5. The robotic wash cell of4, and wherein said object has a variety of surfaces and said six-axisrobotic arm moves said end effector and nozzle along a series ofparticular paths in a multi-directional manner along each of saidvariety of surfaces, each of said particular paths maintaining saidnozzle a desired distance within said effective working range of saidspray from the surface of the object, and said robotic arm articulatingsaid end effector and nozzle and their said direction of aim to remainsubstantially normal to the surface of the object as said robotic armmoves said end effector along each of said particular paths of travel.6. The robotic wash cell of 5 wherein said robotic arm includescomponent members and said component members include a base, first andsecond arm members, a wrist, and a mount with said proximal end, saidbase being rotatably connected to said supporting surface about acentral axis of said base, said first arm member being pivotallyconnecting said to said base, said second arm member being pivotallyconnected to said first arm member, said second arm member having afirst portion that is rotatably connected to a second portion along acentral axis of said second arm member, said wrist being pivotallyconnected to said arm member, and said mount being rotatably connectedto said wrist about a centerline of said mount.
 7. The robotic wash cellof 6 wherein at least one of said paths of travel is arcuate.
 8. Therobotic wash cell of 1 wherein said end effector has an adjacent nozzlealigned parallel to said direction of aim and producing an adjacentspray, said sprays overlapping in said effective working range, and saidsprays being slightly rotated to avoid intersection of said adjacentsprays.
 9. The robotic wash cell of 8 wherein said effective workingrange has an effective cleaning zone with a depth of about two inches.10. The robotic wash cell of 9 wherein said effective cleaning zoneextends from about eight inches to about ten inches from said nozzle.11. A robotic wash cell for cleaning a contaminant from a surface of anobject comprising: a recycling and pressurization system having a watersupply, an oil separator to separate oil from said water supply to apredetermined oil purity level, a filter to filter solids from saidwater supply to a predetermined solids purity level, and a pump topressurize a portion of said water supply to a predetermined pressure; arobot having at least six axes of rotation and an arm having an endeffector with a nozzle in fluid communication with said pressurizedportion of said water supply, said end effector and nozzle having adirection of aim to spray said pressurized water in a spray in saiddirection of aim, said robot arm to move said end effector and nozzle apredetermined distance from the surface of the object and articulatesaid end effector to direct said direction of aim of said spraysubstantially normal to the surface, and to move said end effector alonga path of travel while maintaining said nozzle said predetermineddistance from the surface of the object and articulating said endeffector to maintain said direction of aim of said spray substantiallynormal to the surface of the object as the end effector moves along saidpath of travel, said spray being returned via said recycling andpressurization system to said water supply.
 12. A robotic wash cellusing water for cleaning a contaminant from a surface of an objectcomprising: a recycling and pressurization system having a water supply,a robot having at least six axes of rotation and an arm having an endeffector with a nozzle in fluid communication with said pressurizedportion of said water supply, said end effector and nozzle having adirection of aim to spray said pressurized water in a spray in saiddirection of aim, said robot arm to move said end effector and nozzle apredetermined distance from the surface of the object and articulatesaid end effector to direct said direction of aim of said spraysubstantially normal to the surface, and t move said end effector alonga path of travel while maintaining said nozzle said predetermineddistance from the surface of the object and articulating said endeffector to maintain said direction of aim of said spray substantiallynormal to the surface of the object as the end effector moves along saidpath of travel, said spray being returned via said recycling andpressurization system to said water supply.
 13. The robotic wash cell of12 further comprising a pump to pressurize a portion of said watersupply to a predetermined pressure.
 14. The robotic wash cell of 12further comprising an oil separator to separate oil from said watersupply to a predetermined oil purity level.
 15. The robotic wash cell of13 further comprising a filter to remove solids from said water supplyto a predetermined purity level.